Consider a schedule S of transactions T1 and T2:
|
T1 |
|
R(X) |
W(X) |
|
R(W) |
|
R(Z) |
|
commit |
|
|
T2 |
R(Y) |
|
|
R(Z) |
|
W(W) |
|
W(X) |
|
commit |
In the above transactions, R(X) stands for read data item X and W(X) stands for write data item X. Also, WAW stands for write after write, and WAR stands write after read.
Which one of the following is/are TRUE about the above schedule?
1
S is conflict serializable
2
Precedence graph of S is acyclic
3
Commit of T2 before commit of T1 is not allowed
4
WAW hazard is from T1 to T2